WASHINGTON — Felons are asking President Bush for pardons and commutations at historic levels as he nears his final months in office, a time when many other presidents have granted a flurry of clemency requests.

Among the petitioners is Michael Milken, the billionaire former junk bond king turned philanthropist, who is seeking a pardon for his 1990 conviction for securities fraud, the Justice Department said. Mr. Milken sought a pardon eight years ago from President Bill Clinton, and submitted a new petition in June.

The requests are adding to a backlog of nearly 2,300 pending petitions, most from “ordinary people who committed garden-variety crimes,” said Margaret Colgate Love, a clemency lawyer.

Ms. Love, who was the United States pardon attorney from 1990 to 1997, said the backlog was overwhelming the vetting system, meaning that many petitions might not reach Mr. Bush’s desk before he leaves office.

“I have cases that date from the Clinton administration,” Ms. Love said. “I have cases that I filed in the last two or three years and have not even gotten any word about the first step of the investigation being authorized. It’s unbelievable.”

A Justice Department office with about half a dozen officials reviews petitions and recommends whether requests should be granted, although presidents are free to disregard its views. Under the Constitution, Mr. Bush can issue a commutation, which reduces a sentence, or a pardon, which forgives an offense and erases the criminal record, to anyone.

But even if a felon’s petition reaches the Oval Office, legal specialists said that most of those seeking mercy from Mr. Bush should expect to be disappointed.